/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    ArffSaver.java
 *    Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.converters;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Vector;
import java.util.zip.GZIPOutputStream;

import weka.core.AbstractInstance;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.RevisionUtils;
import weka.core.Utils;

/**
 * Writes to a destination in arff text format.
 * <p/>
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -i &lt;the input file&gt;
 *  The input file
 * </pre>
 * 
 * <pre>
 * -o &lt;the output file&gt;
 *  The output file
 * </pre>
 * 
 * <pre>
 * -compress
 *  Compresses the data (uses '.arff.gz' as extension instead of '.arff')
 *  (default: off)
 * </pre>
 * 
 * <pre>
 * -decimal &lt;num&gt;
 *  The maximum number of digits to print after the decimal
 *  place for numeric values (default: 6)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Stefan Mutter (mutter@cs.waikato.ac.nz)
 * @version $Revision: 9515 $
 * @see Saver
 */
public class ArffSaver extends AbstractFileSaver implements BatchConverter,
    IncrementalConverter {

  /** for serialization */
  static final long serialVersionUID = 2223634248900042228L;

  /** whether to compress the output */
  protected boolean m_CompressOutput = false;

  /** Max number of decimal places for numeric values */
  protected int m_MaxDecimalPlaces = AbstractInstance.s_numericAfterDecimalPoint;

  /** Constructor */
  public ArffSaver() {

    resetOptions();
  }

  /**
   * Returns an enumeration describing the available options.
   * 
   * @return an enumeration of all the available options.
   */
  @Override
  public Enumeration listOptions() {
    Vector<Option> result;

    result = new Vector<Option>();

    Enumeration en = super.listOptions();
    while (en.hasMoreElements())
      result.addElement((Option) en.nextElement());

    result.addElement(new Option("\tCompresses the data (uses '"
        + ArffLoader.FILE_EXTENSION_COMPRESSED + "' as extension instead of '"
        + ArffLoader.FILE_EXTENSION + "')\n" + "\t(default: off)", "compress",
        0, "-compress"));

    result.addElement(new Option(
        "\tThe maximum number of digits to print after the decimal\n"
            + "\tplace for numeric values (default: 6)", "decimal", 1,
        "-decimal <num>"));

    return result.elements();
  }

  /**
   * returns the options of the current setup
   * 
   * @return the current options
   */
  @Override
  public String[] getOptions() {
    int i;
    Vector<String> result;
    String[] options;

    result = new Vector<String>();

    if (getCompressOutput())
      result.add("-compress");

    result.add("-decimal");
    result.add("" + getMaxDecimalPlaces());

    options = super.getOptions();
    for (i = 0; i < options.length; i++)
      result.add(options[i]);

    return result.toArray(new String[result.size()]);
  }

  /**
   * Parses the options for this object.
   * <p/>
   * 
   * <!-- options-start --> Valid options are:
   * <p/>
   * 
   * <pre>
   * -i &lt;the input file&gt;
   *  The input file
   * </pre>
   * 
   * <pre>
   * -o &lt;the output file&gt;
   *  The output file
   * </pre>
   * 
   * <pre>
   * -compress
   *  Compresses the data (uses '.arff.gz' as extension instead of '.arff')
   *  (default: off)
   * </pre>
   * 
   * <pre>
   * -decimal &lt;num&gt;
   *  The maximum number of digits to print after the decimal
   *  place for numeric values (default: 6)
   * </pre>
   * 
   * <!-- options-end -->
   * 
   * @param options the options to use
   * @throws Exception if setting of options fails
   */
  @Override
  public void setOptions(String[] options) throws Exception {

    setCompressOutput(Utils.getFlag("compress", options));

    String tmpStr = Utils.getOption("decimal", options);
    if (tmpStr.length() > 0) {
      setMaxDecimalPlaces(Integer.parseInt(tmpStr));
    }

    super.setOptions(options);
  }

  /**
   * Set the maximum number of decimal places to print
   * 
   * @param maxDecimal the maximum number of decimal places to print
   */
  public void setMaxDecimalPlaces(int maxDecimal) {
    m_MaxDecimalPlaces = maxDecimal;
  }

  /**
   * Get the maximum number of decimal places to print
   * 
   * @return the maximum number of decimal places to print
   */
  public int getMaxDecimalPlaces() {
    return m_MaxDecimalPlaces;
  }

  /**
   * Returns the tip text for this property.
   * 
   * @return tip text for this property suitable for displaying in the
   *         explorer/experimenter gui
   */
  public String maxDecimalPlacesTipText() {
    return "The maximum number of digits to print after the decimal "
        + "point for numeric values";
  }

  /**
   * Returns the tip text for this property
   * 
   * @return tip text for this property suitable for displaying in the
   *         explorer/experimenter gui
   */
  public String compressOutputTipText() {
    return "Optional compression of the output data";
  }

  /**
   * Gets whether the output data is compressed.
   * 
   * @return true if the output data is compressed
   */
  public boolean getCompressOutput() {
    return m_CompressOutput;
  }

  /**
   * Sets whether to compress the output.
   * 
   * @param value if truee the output will be compressed
   */
  public void setCompressOutput(boolean value) {
    m_CompressOutput = value;
  }

  /**
   * Returns a string describing this Saver
   * 
   * @return a description of the Saver suitable for displaying in the
   *         explorer/experimenter gui
   */
  public String globalInfo() {
    return "Writes to a destination that is in arff (attribute relation file format) "
        + "format. The data can be compressed with gzip in order to save space.";
  }

  /**
   * Returns a description of the file type.
   * 
   * @return a short file description
   */
  @Override
  public String getFileDescription() {
    return "Arff data files";
  }

  /**
   * Gets all the file extensions used for this type of file
   * 
   * @return the file extensions
   */
  @Override
  public String[] getFileExtensions() {
    return new String[] { ArffLoader.FILE_EXTENSION,
        ArffLoader.FILE_EXTENSION_COMPRESSED };
  }

  /**
   * Sets the destination file.
   * 
   * @param outputFile the destination file.
   * @throws IOException throws an IOException if file cannot be set
   */
  @Override
  public void setFile(File outputFile) throws IOException {
    if (outputFile.getAbsolutePath().endsWith(
        ArffLoader.FILE_EXTENSION_COMPRESSED))
      setCompressOutput(true);

    super.setFile(outputFile);
  }

  /**
   * Sets the destination output stream.
   * 
   * @param output the output stream.
   * @throws IOException throws an IOException if destination cannot be set
   */
  @Override
  public void setDestination(OutputStream output) throws IOException {
    if (getCompressOutput())
      super.setDestination(new GZIPOutputStream(output));
    else
      super.setDestination(output);
  }

  /**
   * Resets the Saver
   */
  @Override
  public void resetOptions() {

    super.resetOptions();
    setFileExtension(".arff");
  }

  /**
   * Returns the Capabilities of this saver.
   * 
   * @return the capabilities of this object
   * @see Capabilities
   */
  @Override
  public Capabilities getCapabilities() {
    Capabilities result = super.getCapabilities();

    // attributes
    result.enableAllAttributes();
    result.enable(Capability.MISSING_VALUES);

    // class
    result.enableAllClasses();
    result.enable(Capability.MISSING_CLASS_VALUES);
    result.enable(Capability.NO_CLASS);

    return result;
  }

  /**
   * Saves an instances incrementally. Structure has to be set by using the
   * setStructure() method or setInstances() method.
   * 
   * @param inst the instance to save
   * @throws IOException throws IOEXception if an instance cannot be saved
   *           incrementally.
   */
  @Override
  public void writeIncremental(Instance inst) throws IOException {

    int writeMode = getWriteMode();
    Instances structure = getInstances();
    PrintWriter outW = null;

    if (getRetrieval() == BATCH || getRetrieval() == NONE)
      throw new IOException("Batch and incremental saving cannot be mixed.");
    if (getWriter() != null)
      outW = new PrintWriter(getWriter());

    if (writeMode == WAIT) {
      if (structure == null) {
        setWriteMode(CANCEL);
        if (inst != null)
          System.err
              .println("Structure(Header Information) has to be set in advance");
      } else
        setWriteMode(STRUCTURE_READY);
      writeMode = getWriteMode();
    }
    if (writeMode == CANCEL) {
      if (outW != null)
        outW.close();
      cancel();
    }
    if (writeMode == STRUCTURE_READY) {
      setWriteMode(WRITE);
      // write header
      Instances header = new Instances(structure, 0);
      if (retrieveFile() == null && outW == null)
        System.out.println(header.toString());
      else {
        outW.print(header.toString());
        outW.print("\n");
        outW.flush();
      }
      writeMode = getWriteMode();
    }
    if (writeMode == WRITE) {
      if (structure == null)
        throw new IOException("No instances information available.");
      if (inst != null) {
        if (inst instanceof weka.core.SparseInstance
            && inst.dataset().checkForStringAttributes()) {
          // check for single valued string attributes
          for (int i = 0; i < inst.numAttributes(); i++) {
            if (inst.attribute(i).isString()
                && inst.attribute(i).numValues() == 1) {
              String theVal = inst.stringValue(i);
              inst.attribute(i).setStringValue(
                  weka.core.Attribute.DUMMY_STRING_VAL);
              inst.attribute(i).addStringValue(theVal);
              inst.setValue(i, 1);
            }
          }
        }

        // write instance
        if (retrieveFile() == null && outW == null)
          System.out.println(inst.toStringMaxDecimalDigits(m_MaxDecimalPlaces));
        else {
          outW.println(inst.toStringMaxDecimalDigits(m_MaxDecimalPlaces));
          m_incrementalCounter++;
          // flush every 100 instances
          if (m_incrementalCounter > 100) {
            m_incrementalCounter = 0;
            outW.flush();
          }
        }
      } else {
        // close
        if (outW != null) {
          outW.flush();
          outW.close();
        }
        m_incrementalCounter = 0;
        resetStructure();
        outW = null;
        resetWriter();
      }
    }
  }

  /**
   * Writes a Batch of instances
   * 
   * @throws IOException throws IOException if saving in batch mode is not
   *           possible
   */
  @Override
  public void writeBatch() throws IOException {
    if (getInstances() == null)
      throw new IOException("No instances to save");
    if (getRetrieval() == INCREMENTAL)
      throw new IOException("Batch and incremental saving cannot be mixed.");
    setRetrieval(BATCH);
    setWriteMode(WRITE);
    if (retrieveFile() == null && getWriter() == null) {
      Instances data = getInstances();
      System.out.println(new Instances(data, 0));
      for (int i = 0; i < data.numInstances(); i++) {
        System.out.println(data.instance(i).toStringMaxDecimalDigits(
            m_MaxDecimalPlaces));
      }
      setWriteMode(WAIT);
      return;
    }

    PrintWriter outW = new PrintWriter(getWriter());
    Instances data = getInstances();

    // header
    Instances header = new Instances(data, 0);
    outW.print(header.toString());

    // data
    for (int i = 0; i < data.numInstances(); i++) {
      if (i % 1000 == 0)
        outW.flush();
      outW.println(data.instance(i)
          .toStringMaxDecimalDigits(m_MaxDecimalPlaces));
    }
    outW.flush();
    outW.close();

    setWriteMode(WAIT);
    outW = null;
    resetWriter();
    setWriteMode(CANCEL);
  }

  /**
   * Returns the revision string.
   * 
   * @return the revision
   */
  @Override
  public String getRevision() {
    return RevisionUtils.extract("$Revision: 9515 $");
  }

  /**
   * Main method.
   * 
   * @param args should contain the options of a Saver.
   */
  public static void main(String[] args) {
    runFileSaver(new ArffSaver(), args);
  }
}
